Factual error: The timeline for this film is incorrect. The flight Lisa takes is a red eye from Dallas to Miami. Non-stop flights between those cities takes 2 1/2 hours. Even with the west to east time change, this isn't long enough for a red eye. Shortly after take off, the clock in her father's house reads about 11:15pm. The plane lands after sunrise in Miami.
Factual error: The boat "Rapture" lacks any Florida FL registration decals or any decals. If the boat was registered in Florida, the FL decals should be seen above the waterline and at the bow of the boat.
Answer: These are tech-savvy terrorists. Not only were they closely watching Keefe, but also Lisa, who is integral to their assassination plot. The assassins were monitoring their every move, intercepting cell phone calls, probably hacking into the hotel's and the airline's computers, and so on. It is unknown how Jackson got a seat right next to Lisa, but as it's a late-night Red Eye flight, there would likely be fewer passengers and he could have managed to be seated next to her or somehow got the airline to switch him with another passenger.
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